FP6 priority
1.1.3   Nanotechnologies and Nanosciences, Knowledge-based Multifunctional Materials and New Production Processes and Devices
Title of the proposal

Superconducting weak links for SQUIDs and microwave devices

Slovak Academy of Sciences, Institute of Electrical Engineering
Dubravska cesta 9, 842 39 Bratislava, Slovak Republic
Dr. Stefan BENACKA
+421 2 4775820

Research subject for a potential FP6 project

The Cryoelectronic Dept. (CD) of the IEE SAS more than 20 years has been engaged in a preparation of superconducting thin films, study of weak links (Josephson effects) and SQUIDs. High-temperature (cuprates) and medium temperature (nanocrystalline MgB2) superconducting thin films of high quality are currently prepared. Dc and microwave characterisation of weak links (step-edge, bicrystal, sandwich), and micrometer and submicrometer thin film structures are utilized, as well as study of the surface and interface properties by tunnelling spectroscopy. The activity includes also development of SIS type junctions with pronounced Josephson effects. The current interest is to develop and investigate cuprate thin film structures on substrates with surface tilted from the small-index crystallographic planes (tilted-axes substrates, TAS) and structures based on MgB2 thin films. The tasks include: study of tunnelling barrier using ion beam modified interface of cuprate films, preparation of high quality cuprate thin films on TAS, preparation of thin film heterostructures on TAS for passive microwave components, including structures incorporating magnetic metal-oxide layers, investigation of intrinsic Josephson effects in the tilted-axes thin films (for THz mixers) and basic study of SIS tunnel junction prepared on MgB2 superconducting thin films. Technological possibilities of the CD include vacuum deposition techniques and ion beam etching arrangements, photolithographic labs. and access to electron beam lithography. Experimental basis comprises low temperatures (1.3-300K), high magnetic field and microwave (106-1011 Hz) facilities, and methods of tunnelling spectroscopy. The group achieved stimulating results during the participation in projects of international cooperation (PECO, INCO, INCO-Copernicus, INTAS). Organisation of international Workshops on Weak Superconductivity by the CD is very appreciated.

Recent international cooperation of the research team

Twente University, Enschede, The Netherlands; Technical University of Denmark, Lyngby, Denmark; Institute of Radio engineering and Electronics RAS, Moscow, Russia; Institut fuer Schicht-und Ionentechnik, FZ Juelich GmbH, Juelich, Germany; Chalmers University of Technology, Gothenburg, Sweden; Institute of Physics PAS, Warsaw, Poland; Institute of Electronics BAS, Sofia, Bulgaria

Proposerīs relevant publications related to the research subject

Plecenik A., Grajcar M., Seidel P., Benacka S.: Investigation of HTS surface properties by tunneling spectroscopy, in: Studies of High Temperature Superconductors, ed. A.V.Narlikar, Nova Sci.Publ., New York 1996, pp.75-123; Belogolovskii M., Grajcar M., Kus P., Plecenik A., Benacka S., Seidel P.: Phase-coherent charge transport in superconducting heterocontacts, Phys.Rev B 59, 9617 (1999); Plecenik A., Strbik V., Chromik S., Zuzcak M., Benacka S., Interface properties of YBaCuO/I/metal juncttions with native and artificial tunneling barriers, Superc.Sci.and Technol.13, 1180 (2000); Hlinka J., Gregora I., Pokorny J., Plecenik A, Kus P., Satrapinsky L., Benacka S.: Phonons in MgB2 by polarized Raman scattering on single crystals, Cond-mat/0105275, Phys.Rev.B 64, 140503 (2001); Plecenik A., Benacka S., Kus P., Grajcar M.: Superconducting gap parameter of MgB2 obtained on MgB2/Ag and MgB2/In junctions, Cond-mat/0104038, Physica C 368, 251 (2002)